/**
 * @author jarvan
 */
public interface GenericStackInterface<E> {
    /**
     * Add new Top item. and the length of list  + 1
     * @param newTopItem new top item.
     */
    void push(E newTopItem);

    /**
     * Pop a top item.and the length of list -1
     * @return top item.
     */
    E pop();

    /**
     * Get a top item,but the length of list do not change .no item need move.
     * @return top item.
     */
    E peek();

    /**
     * Return true if the list have not any item.
     * @return Return true if the list have not any item.
     */
    boolean isEmpty();

}
